Method and apparatus for hardening brake drums and the like



June 19, 1928.

W. G. HILDORF METHOD AND APPARATUS FOR HARDENING BRAKE PRUMS AND THE LIKE 2 Shets-Sheet Filed July 22, 1925 June 19, 192 8.

W. G. HILDORF METHOD AND APPARATUS FOR HARDENING BRAKE DRUMS AND THE LIKE Filed July 22, 1925 2 Sheets-Sheet Jnto'o "idler a. 157M012 MSW,

the like. V

gards durability.

Patented June 19, 1928.

UNITED 1,674,470 PATENT or l-"tics.

WA TER e. HILD RF; F LANSING, MICHIGAN, AssIGNon o REO MOTOR CAR COMPANY,

or LANSING MIGI-IIGAN, a C RPOR I N or MICHIGAN;

METHOD AND APPARATUS ronrmnnnmne BnAKnnRnMs AND THE LIKE.

A ncationmea July 22, 1925'. *;S e ria1 No. 5,372.

. .This invention relates to a method. and apparatus for hardening brake drums and The invention finds particular utility 'in connection with brake drums formed of pressed steel which during manufacture are made from metal which has first been rolled into sheets i and thenpressed into drums.

The-inherent resiliency of the metal creates a tendency When thus CllStOlftGCl, to spr ng back. into its original shapeso that brake drumsformed of pressed steel donot accu rately retain their shape With the result that they are:inefficient in operation and as rev ,It is furthermore essenanj Fig. 1 hav ng the desired" shape and tialthat-relatively. hard bearing surfaces be provided on the brake drum to prevent the formation byfwear, of particles ofmetal 1 v parted thereto,]a nd to produce sufiiciently from the, drum which charge or become lodged in the fabr c ofthe brake band, as such particles-cause arapid wearing o-ut and v deterioration of the drum. I

These. aforementioned objections are overcome-by formingthe brake drum ofa steel having a sufliciently high percentage ofcar bon to enable, the same tobe hardened and during the manufacture of the brake drum to heat the saine and shape it on dies and to theniuniformly chill the drum to harden it particularlyat its Wearing surfaces hile holding 1t on a dieto preventdistortionfrom irregular shrinkage. The invention also contemplates protection to the'Web duringquen-ehing whereby the same may retain itstoughness and its abilityto resist shocks.

An object of the; present invention is to provide a ,niethod and apparatus for uni.- formly chilling the, brake drum to harden the bearing surfaces thereof hile protect- 7 ing the Web and for retaining the drum during this hardening process in theshape previously imparted thereto.

The invention also has among its objects to simplify render more efficient, and im-Y r prove generally-methods and apparatus of and these, as -oll as other this character,

objects. advantages, fea tures. ofv construction, and novel steps in the 11'lBtli0ClVlll.-l30 made more-apparent as this ClGSCI'lDtlOD proceeds, especiallywhen considered in connection with the accompanying drawings wherein Figure 1 1s viewthrough an apparatus construct-ed in f accordance with this invention a central vertical sectional In practice the brake drum is formed jreferahly of steel of a high carbon contentyvhich isfirstrolled into sheets, heated andpressed nto drums lOsuch as shown dimensions. I In order to harden the steel so that 1t will retam the shape previously imhardened-surfaces to withstand thestrains inpztrted thiereto during use, I provide the followv ng apparatus which receives the pre- ,=.v iously shaped heated drum during the g uenching vor chilling and hardening operat1on. i

L This lapparatusnonsists essentially of'a base orf bed plate .11 upon which isiniounted a pluralityiof segmental die- Or form mem- {bers 12 arrangedradially to a centrallydisposed Train 13; The, segmental Edi membe 12 arer-adially displaceable by the 'r'aijn '13,

, this adjustment or; displacement of the segvmental members 12 re sulting from'the engagement of the taperedlportion 145 .of the ram vith the eam surface 15 formed on each segmental member 12. fGon-sequently during the downward movement' of; the ram the segmental members'12 move outwardly and assume a position in hichtheir put-side diameter 1s coincldent with the desired 1n- SldQ d ameter of the hralre I drum.

Each segrnentaljdie member is formed withza recessed or cutaway portion 18, which together form v substantially a circumferential recessadapted to receive the Web portion 119 of the brake drum 1O. The drum" portion QO-Ofthe brakefdruin lies vadjacent totand is engaged bythe outer face of each die segment 12 these faces .beingfprovided with a plurality of vertic,ally"ex'tending grooves or scallops 21 for a purpose to'be more;fully hereinafter referred to. ;S e cured to the ram 13is a cap-plate2 2, hich'inthe lowered positionof the ram, engages the up'per faeeo ath -fl bew o t el zrals glru and securely clamps the brake drum, holding the same in the circumferential recess 18 and against the segmental die members 12. A fixed relationship exists between the cap plate 22 and the tapered portion 14: of the ram, sov that when the web 19 of the drum,

I grooves or channels extend outwardly past the outer periphery of the brake drum Where a circumferential plate 27 may be arranged beneath the outer peripheral edge of the drum to constitute a baffle or interceptor. The stream of chilling or quencing fluid divides at the battle plate 27, part flowing upwardly against the outer surface of the brake drum and part through the channels or grooves 21 formed in the die segments 12, thus engaging the inner surface of the drum portion of the brake drum, and then through apertures 28 to grooves 29, through apertures in cap plate 22 and out through passages in the head of the upper die.

While the baffle plate 27 has been described as an element of this apparatus it may be eliminated if desired. However this battle plate protects the edge of the drum from the sudden shock of the quenching medium whereby a uniform cooling of the drum is assured and the possibility of warpage due to uneven cooling eliminated.

The web portion 19 of the drum is clamped between the cap plate 22 and the recessed portions 18 of the segments 12 and is consequently protected from the quenching medium so that it will not be hardened to the same extent as thebearing surfaces of the part 20 of the drum and will therefore be relatively tougher.

The upper head indicated generally at 25, serves as a support for the cap plate 22 and these parts together with the ram 13 move as a unit and comprise the upper part of the die. After the heated brake drum 10 has been placed loosely upon the lower die part comprising the segments 12 and plate 11, the upper die part is moved toward the lower die part to expand the segments and grip the drum in the aforedescribed manner. The upper and lower dies now descend together into the quenching medium causing the quenching mediunrto issue in streams through the apertures 28 as also above de scribed. During this descent both die parts as well as the drum are completely sub merged in the quenching medium and are allowed to remain stationary for a period of time sufiicient to permit the drum to fully cool. The die parts then ascend together shown) whereupon the upper die continues thus separating the die parts; The relative movement of the upper die part disengages the tapered part 14 of the ram from the segments allowing these segments to free themselves from the drum whereupon the strippers about to be described, function.

For removing the chilled drum from the die members or form I provide a plurality, preferably three, of strippers 31 secured to the cap plate 22. Each stripper consists essentially of a hollow member 32 havinrr a hooked portion 33 adapted'to engage un er the edge of the drum. A second member 34 projects into the hollow portion 35 of member 32 and is provided with ahead 36 having an irregular shape substantially similar to the cross-sectional shape of the hollowlportion 35 whereby relative rotative movement between the two stripper parts is prevented. A spring 37 extends between head 36 and the lower end of recess 35 whereby the stripper is both extensible and compressible.

One of the strippers is hinged by pivot-v ally conneeting the member 34 thereof as at 38 to a hinge part 39 secured to cap'plate 22.

A spring 4-0 also secured to the cap plate ex- 7 tends over and bears against a flattened portion ll formed on the upper end of stripper part 3 1-. Owing to the arrangement of pivot 38 spring 10 tends normally to swing the stripper inwardly toward the brake drum whereby the hook portion 33 will engage thereunder. However, when cap plate22 has been raised and brake drum 10 stripped from the die segments 12 the drum may be removed by swinging this hinged stripper upwardly to a substantiallyhorizontal position, the stripper being retained in this position by the engagement of the spring'40 with the flat face 12 of the stripper. Since all of the strippers are of the same length and are equally spaced circumferentially of the drum, the drum may be vertically lifted without appreciable tilting and binding. The springs 37 also permit an initial extension of the strippers sufiicient to insure 'a freeing of the drum by the die segments prior to the stripping operation.

In Fig. 5 a slightly modified'form of apparatus is illustrated, the construction being altered for the accommodation ofv a slightly. different shaped brake drum 13 which is shaped to provide an intermediate inclined portion 4-4. Consequently the guide segments 12 have an inclined surface arranged to lie adjacent to but slightly spaced from the inclined portion 414 of the drum. In this form of apparatus the cap plate 46 is formed with grooves 17 for conducting the quenching fluid to an outer walledportion 418 of the cap plate. In all other respects the modified form of apparatus shown it'll 7 her preventin quenching in Fig. 5 is substantially identical with the form previously described.

IVhile the invention has been described and illustrated herein somewhat in detail it :will be immediately apparent that various 'modificationsmay be resorted to without departing from the spirit and scope of the invention and to this end reservation is made to make such changes as maycome within the purview of the accompanying claims.

What I claim as my invention is:

1. In a method of hardening brake drums, the steps consisting of, supportingthe heated previously shaped drum upon a die memg shrinkage of said brake drum beyond the desired diameter while maintaining the outer periphery free from contact, and simultaneously chilling both sides of the drum member to insure uniform shrinkage.

2. In an apparatus for treating brake drums, an adjustable die adapted to loosely receive a heated brake drum, means for adjusting said die to the desired inside diam-- eter of the drum portion of the brake drum, I

means for clamping the web portionof the brake drum upon said die and means for substantially simultaneously supplying a fluid to both sides of said drum portion to cause the same to uniformly shrink into engagement with said adjusted die.

3. In an apparatus of the class described, a die comprising a plurality of adjustable segments, means for adjusting said segments, means for clamping a brake drum to be hardened by its web portion to said die,

and means for supplying a quenching fluid to the drum portion only of said brake drum.

l. In an apparatus of the class described,

a die formed of a plurality of hollow channeled segments, means for adjusting said segments radially, means carried by said adjusting means for clamping a drum in place on said die, and means for directing a quenching fluid through said segments and into engagement ing the same. 1

5. In an apparatus'for hardening brake. drums and the like, a shape retaining die adapted to receive a drum to be chilled, means for adjusting said die, means for directing a quenching fluid into engagement with said drum, and means for initially defleeting said fluid away from the outer free edge of the drum. e. In an apparatus for hardening brake drums and the like, a holding die adapted to receive a drum to be hardened, clamping means therefor, and strippers mounted for movement relative to the die, for engaging said drum. 7 1 a 7. In an apparatus of the class described, an adjustable holding die adapted to receive with said drum for chilla brake drum to be chilled, reciprocable means for adjusting said die and for clamping said drum in place, and strippers carried by said means, and mounted for engagement with said drum for removing the same from said die. 8. In an apparatus of the class described, anadjustable holding die adapted to receive a brake drum to be I chilled, reciprocable means for adjusting said die, and for clamping said drum in place, strippers, a hinge connection between a stripper and said re-, ciprocable means, and a spring member associated therewith for holding said stripper in operative or inoperative position.v

9. In an apparatus of the class described, an adjustable holding die adapted to receive a brake drum to be chilled, reciprocable means for adj usting said die, and for clamping said drum in place, and strippers carried by said means, and mounted for engagement with said drum for removing the same fronr said die, said strippers each comprising a pair of resiliently connected sections.

10. An apparatus for treating brake drums comprising, a die, means engaging the web portion of the brakedrum for holding the same upon said die and for protect' ing the same and means for chilling the drum portion of the brake drum by a quench ing fluid to harden the same.

11. In an apparatus of the class described, a die "formed of a plurality of channeled segments, adjusting means for said segments, means for clamping a brake drum upon said die and means for directing a quenching fluid through said channels into engagement. with said drum for chilling the same.

12. In an apparatus of the class described a die formed of a plurality of segments provided with channels on their outer periphery, means for adjusting said segments and for clamping a brake drum upon said die and means for directing a quenching fluid through said channels into engagement with said drum for chilling the same.

13. An apparatus of the class described comprising, a shape retaining die adapted to receive a brake drum to be chilled, means for directing a quenching fluid into engagement with said drum and means for initially defleeting said fluid away from the outer free edge of the drum. V

14. An apparatus of the class described comprising, a shape retaining die adapted to receive a brake drum to be chilled, means for directing a quenching fluid substantially simultaneously into engagement with both sides of said drum and a baflie for initially deflecting said fluid away from the outer free edge of said drum.

In testimony whereof I affix my signature;

WALTER G, I-IILDORF. 

